Researchers Claim That Time Delays In Vending Machines Prompt Healthier Snack Choices

Posted On: 4/3/2017

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TAGS: vending machine, delayed access, vending machine, Society of Behavioral Medicine, Brad Appelhans, Rush University Prevention Center, DISC, Delays to Improve Snack Choices

SAN DIEGO -- Delaying access to high-calorie foods and snacks in vending machines can shift people's choices to purchase healthier snack options, according to new research. Preventive medicine experts at Rush University Medical Center presented the findings on March 31 at the Society of Behavioral Medicine 's annual meeting in San Diego. The study was funded by the National Institutes of Health.

"Having to wait for something makes it less desirable," said Brad Appelhans, clinical psychologist at the Rush University Prevention Center, and the study's lead investigator of the study. "Research shows that humans strongly prefer immediate gratification, and this preference influences choices and behavior in daily life."

Appelhans and other researchers developed a new technology called DISC (Delays to Improve Snack Choices) that employs a "delay bar" to separate "healthier" snacks from the less nutritious options. When a patron selects a less nutritious snack, the system begins a 25-second time delay before the machine releases it from the vending machine.

The DISC-equipped vending machine also has an LED screen, which displays the delay times for "less healthy" snack items, and a delivery countdown, which allows the customer to change his or her snack choice to a healthier option.

The delay reportedly yielded a 2% to 5% increase in the proportion of total purchases from healthy snacks. "Also, we found that the delay did not harm total sales volume or vending revenue, which is important to vending machine operators," said Appelhans.

The study of the DISC vending machine system looked at the following six interventions in three locations between June 2015 and August 2016:

» No intervention
» 25-second time delay on less healthy snacks
» 25¢ discount on healthy snacks
» 25¢ tax on less healthy snacks
» 25-second time delay on less healthy snacks and 25¢ discount on healthier snacks
» 25-second time delay and 25¢ tax on less healthy snacks

"Healthy" snacks had to meet five of seven criteria: less than 250 calories per serving; 35% or fewer calories from fat; less than 350mg sodium per serving; no trans fat; less than 5% of daily value of saturated fat per serving; more than 1g. dietary fiber per serving; less than 10g. added sugar per serving.

Healthy snack purchasing reportedly increased during the time delay condition, as well as when the machines were set to 25¢ discounts for healthier options or with a 25¢ additional tax on snacks that did not meet the "healthy" criteria.

"Our findings with the DISC vending machine system suggests that relatively brief time delays can nudge people to purchase healthier snacks at least some of the time. The beneficial effect on snack choice is about as large as that seen with discounts, but unlike discounts, time delays do not harm the total revenue of vending machines," Appelhans said. "This could be a viable option for vending machine owners to offer good, healthy snack options while keeping their sales and avoiding out-of-pocket costs."

The study included 32,662 vending machine snack sales. "Healthy" snacks were color coded and labeled to differentiate them from their traditional counterparts. The machines also had clear signs indicating that regular snacks would vend after a 25-second time delay. A touchscreen menu explained the system's delay mechanism and a countdown timer.

The Society of Behavioral Medicine has 2,200 members who are scientific researchers, clinicians and educators.